Impregnated fiberboard



July 21, 1942. c: R. Ecm-:RT `2,290,741.

`IMPREGNA-TED FIBERBOARD l Filed MarGh 5, 1958 Patenteduly A21,1942.,

'iMPREGNA'rEn FiBEaoAnn Clarence R. Eckert, Englewood, N. J., assigner to The Celotex Corporation, Chicago, Ill., a corporation of Delaware Application March 3,

6 Claims.

In the past it has been more or less common to saturate various fibrous products, such as fiber insulation board, with `various asphalts, waxes, resins, and the like in order that the such so saturated ber board products might be'particularly adaptable for certain uses. Insofar asis known in the past, all of the such saturated 'fiber 4board products have had substantially uniform impregnation either complete or partial and so far as is known heretofore, no attempt has been made to bring about the impregnationjof such materials in a manner so las to deliberately produce a such product having a portion thereof impregnated with amaterial of one hardness Vand a further portion thereof impregnated with a material of a differing hardness.

In the above reference to the impregnation of a iber board product with substances of different hardness in different portions thereof, reference is meant to be made to impregnation through the thickness of the such material as distinguished from the impregnation of a portion of the area thereof, but while different impregnations through the thickness of the fiber board product-are particularly referred to in connection with the invention hereof, it is to be understood that the invention is applicable to provide different impregnation of different areas of ber bard materials. v

In certain uses of impregnated ber board products, as for example rin the use o f such for floor surfacing materials, it is advantageous to have a portion thereof impregnated with a relatively soft or yielding material and to have another portion thereof impregnated With a relatively hard and unylelding material whereby the hard andunyieldin'g impregnated portion surface provides a durable Wearing surface, and the portion which is impregnated with the relatively soft and yielding substance serves as a cushion for the relatively hard and unyielding Wearing surface portion.

It is an object of this invention to produce a fiber board product which is impregnated diierentially, that is wherein portions thereof are impregnated with a relatively soft and yielding substance and other portions thereof are impregnated with relatively` hard and unyielding substances.

further objects ofthe invention will become ap.

parent on reading the following specification 1938, Serial No. 193,718v

(c1. n1-ss) t when taken in connection 'with the accompanying'drawin'g. .f y

In the accompanying drawing: f

Figure 1 is a perspective of an: impregnated ber board produced in accordance with the` invention hereof; Figure 2 shows diagrammatically a means for carrying out the process of the inventiony. Figure 3 is a perspective of animpregnated ber board in which different areasare impregnated with different materials as distinguished from such product in which the diierentyimthickness of the board; and l l5 Figure 4 is a diagrammatic 'view-of the means for carrying out the impregnation l illustrated` in 1 In Figure 1 there is illustratedan impregnated fiber insulation board indicated generally bythe numeral I0 and `in which the lower portion Ilfis impregnated with a relatively soft and` yielding substance, whereas the upper portion 'I2 thereof is impregnatedl with a relatively` hard and vun-v Y yielding substance. Preferably, i.` the fiberlinsu.- lating board Il! is al sheet ofxbertboard ordinarily manufactured and sold as vfiber insulating board, that is a relatively open and porousfboard formed of relatively large fibers and.t characterized by a weight of approximately 2/3 1b. per sq. ft. per- 1/2 inch-of thickness ywith a `conductivity of approximately 0.33 B. T. U. Theplower lor yielding portion of ,the yfiber yboard lil-may be impregnated as at Il with a relatively .lowmelting point asphalt or relativelyllow-melting point wax, or resin, pitch or gum or other moreor less generally similar impregnating substanceas and unyielding portion l2r which mayjbe impregnated with a high meltingpointasphalt, gilsonite, a high melting point Wax, resin, pitch,` or, gum, or generally similar relativelyhard and unyielding material. l

Y A method of impregnating -a fiber board lin accordance with that portion ofthefinvention hereof illustrated in Figure1,\ that isin connection with the preparation of a saturated ber board wherein one portion of .e the `thickness is impregnatedV withva material of certain vcharac;- teristics andthe remainder vof thewthicknessqis impregnated with a materialof `different characteristics, is .diagrammatically illustratedfgin Figure 2* l* .'.s l In Figure 2 there yis .provided a suitablef'conveyor system whichwfor the purposes VofV illustra- 55 tion is indicated as a series of conveyor rolls i3 pregnations are of vdifferent portions through the distinguishing from theupper or relatively ,hardwith which cooperate a series of top guide rolls I4, all of which rolls or any suitable portion thereof may be appropriately driven in order that the sheet of fiber board may be carried through the apparatus to be subjected in its travel to the various steps of treatment which will result in the desired finished product. Over a portion of the conveyor rolls I3 there is provided what will be termed an iron I 5 which is a hollow metal box having if desired appropriate directing channels therein to cause a fluid circulated therethrough to take a tortuous path and which iron is heated by Aa circulating iluid medium flowing into and out from the respective connections I8 and I1 of the iron.

It is to be understood that the heating fluid which is circulated through the iron I5 may be any suitable fluid of the required temperature and having such specific heat that the volume thereof which can be passed through the iron will provide therequired amount of heat to ac'- complish the desired results. As an example of heating medium which may be used, there are suggested as practical high melting point asphalts, oils, mercury, or mercury vapor, or other like or similar fluid which when in highly heated condition at about 500 F. preferably may be circulated to provide the required heat. `It is of course to be understood that the iron I5 is suitably positioned with respect to the conveyor I3 so that it will suitably bear upon the upper surface of a board II when it is passed through the apparatus.

In the direction, located just ahead of the iron I5, when considered in the light of the motion of material through the apparatus, there is a distributor I8 which is adapted t0 appl? to the surface of the board I a suitable saturant material, which saturant is applied just prior to the passage of the sheet I0 under the iron I5. In this first phase of the treatment of the board as has just been described, there isA applied to a surface of the board and to a .predetermined depth a substance such as a high melting point asphalt or the like which is ironed into the surface or driven thereinto by the action of the hot iron as the board I0 carrying on its surface the such treating substance passes under the heated iron I5. v

As the second stage in the operation of the apparatus the board I0 which emerges from under the iron I proceeds on the conveyor I3 to be carried into a suitable tank I9 or the like containing therein the second saturant which is designed to saturate the remainder of the board I9 not theretofore saturated by the treatment under the iron I5. The board is carried under the surface of the saturant which is contained in a tank I9 and which may be suitably heated if required and is then carried up out of the saturant and may continue on the conveyor to pass under a water shower 20 and finally between squeeze or squeegee rolls. The water shower 20 serves to somewhat cool the board at this stage of its productionand squeegee rolls 2| serve to remove any excess water from the surface of the product before Jit is taken away for storage.

As an example of the. surface saturation which may be accomplished under iron I5 and if a relatively hard surface is desired, petroleum pressure pitch maybe used, or gilscnite, or an equivalent petroleum residual asphalt may be used, or other like or similar saturant with relatively high melting point, say 185-400 M. P. (A. S. T. M. ring and ball method), may be employed in this stage of the process. The high melting :point saturant may be applied to the surface of the board I0 by the distributor I8 either in the form of powder or as a liquid if there is provided suitable means for heating and conveying the such liquefied saturant to the distributor member I8. 'I'he coating of high temperature saturant applied to the surface of the board as Just described will be driven into the upper portion of the board I0, as at I2, as the board is carried through the apparatus under the hot iron I5.

For saturating the remainder of the board,

that is the portion indicated by the numeral II with the relatively low temperature saturant,

there may be used low melting point petroleum pressure pitch of say M. P. ring and ball method of test, or the equivalent residual asphalt, or coal tar, or suitable blends or combinations thereof providing a saturant having approximately the fluidity of 40` sec. Furol viscosity for 60 c. c. at a. reasonable temperature say at around 350 F., a temperature at which the saturant in the upper portion I2 of the board does not become similarly fluid.

' It is of course understood that depending somewhat upon the temperature and fluidity of the saturant at such temperature that the iron I5 is of proper length so that the saturant applied at the distributor I8 will be suitably driven into the surface of the board and that the period of lsubmergence of the board in the saturant in the tank I9 is 'such that there is time allowed for the saturation of the lower part of the board with the low temperature saturant material.

In applying this invention to the saturation of areas of a board I 0 as distinguished from the differential saturation of different portions through the thickness, an apparatus differing from that hereinbefore described will be used and to saturate a portion 25 of a board with a relatively hard saturant as distinguishing from the saturation of the remainder of the board 26 .with a relatively soft saturant, there may be used an apparatus such as is illustrated in Figure 4.

In Figure 4 there is illustrated a suitable table 21 on which may be .placed a board Ill, a portion of the area of which is to be saturated with a relatively hard saturant. There may .be then brought down on the upper surface of the board I0 a box-like structure 28 which is of the size of the area which is to be impregnated with the relatively hard saturant. This box-like structure 28 is open on thel bottom so that the saturant when admitted to this open bottom box will be applied to the upper surface of the board I0 over the portion which is to be saturated. A tight fitting plunger 29 may operate through the open top of the box-like structure 28 and be suitably forced down against the upper surface of the sheet I 8 to force thereinto and therethrough suitable saturant which may have been admitted into the box-like member 28. Of course it is not necessary that plunger 29 be used to force the saturant into the board, .but instead the box-like structure 28 may have a closed top and a high pressure may be applied to the saturant which has been admitted into the box-like structure 28 by suitably introducing for example a gaseous fluid thereinto under high pressure to consequently force the saturant into the board I0. A heating medium may be circulated In addition'to the provision for forcing the saturant into the-board from the upper surface as has been described,.there may be provided on the underside of the table member 21 a suction box such as 30 which may be connected to a v suitable source of suction or vacuum, as by pipe 3l. The tableis provided with suitable slots or openings 32 in that portion thereof over -the suction box and the use of such suction box 3l will assist in drawing the saturant through the thickness of the-board I0, a portion of whichis being saturated.

After the relatively hard and unyielding saturant has been driven through the thickness of a portion of the area as just above described, the

the secondary saturating stage of the complete process of treatment, as was above rst described hereimto be saturated throughout the remainder of its body with the desired relatively soft and yielding saturant and it may then be cooled and squeegeed as was described.

It is to be understood that the specific satu- -such treated board may be then passed through a tion which has been given,'those skilled inthe arts appertaining hereto may readily devise various combinations of the various substances mentioned and of like and/or similar substances which may be used in like manner for the diiferential saturation, as has been herein described.`

' What I claim is:

1- A felted b'er board form sheet comprising a wearing surface and a yielding surface and having a portion thereof from a surface andl extending inwardly therefrom, saturated with a high melting .point petroleum pressure pitch whereby the wearing surface is formed, with the remaining portion thereof saturated with a petroleum pressure pitch of alower melting point whereby the yielding surface for the wearing surface is formed.y

2. A-fel'ted-ber board comprising surfaces oft varying degrees of hardness, a surface thereof,

rantsvand method of saturation as hereinabove described, are intended to be illustrative of the invention and that in the light thereof those skilled in the arts appertaining. thereto may readily perceive other procedures for bringing about the desired results-in connecton--with the saturation and may readily substitute other and different saturants either singly or in combination for those which have been specifically mentioned. It is of course immediately apparent that for the relatively hard and unyielding saturant there may be used a wax of high melting pointand for the saturation with a relatively soft and yieldingsaturant there may be used a relatively low melting point wax. It is also apparent together with an adjacent portion, saturated with a saturant, the remainder of the sheet saturated with another saturant, the one saturant being harder than the other saturant. and softening to a lesser extent as the temperature towhich such saturants may be subjected increases above a temperature of about 65 F. whereby a substantially hard wearing surface is formed.

3. A felted ber board comprising` a wearing surface and ayielding surface, a portion of the thickness thereof Esaturated with a vsubstance lof that class represented by l85400 M. P. (A. S. T. M. ring and ball method) petroleum pressure pitch, oil and coal tar pitch of equivalent hardness, and gilsonite, forming a wearing surface and the remainder ofthe board saturated with that class of substance represented by petroleum pressure pitch of 120 M. P. (A. S. T. M. ring and that various heat hardening resins may be employed or thermo setting resins may be employed and that in fact there are many and various substances which may be used for the saturation in lieu of those specifically mentioned. 'I'he essentials of the saturation processes are that the first saturation is with a substance which will not be adversely affected by the treatment comprising the second or final saturation. As an example ,of the saturation will not cause the polymerized portion of the resin to redissolve and of course if resins are used with solvents respectively not solvents for the other resin used, it is readily understood after the solvent used in the first step of the process has been driven off that the second saturation of the process will not adversely aect the rst stage of the saturation. As a specific example of different wax which may be used, there may be used montan wax for the high melting point saturation 'and low melting Daramn for the second phase of the process. As hereinbefore mentioned in view of the descripball method), and oil and coal tar pitch of similar hardness forming a yielding surface. l

4. A felted ber board form sheet, comprising a wearing' surface and .a yielding surface and having a portion thereof, from a surface and extending inwardly therefrom, saturated with a waxy material of high melting point whereby the wearing surface is formed, the remaining portion thereof saturated with a waxy material of a meltingv point lower than the melting point of the aforesaid waxy material whereby the yielding surface is formed.

5. A felted fiber board form sheet, comprising a wearing surface and a yielding surface and having a portion thereof, from a surface and extending inwardly therefrom, saturated with montan wax whereby the wearing surface is formed, the remaining portionthereof saturated with paraffin wax of a melting point lower than the melting point of the aforesaid montan wax whereby the yielding surface is formed.

6. A felted ber board comprising surfaces of varying 'degrees of hardness, a surface thereof, together with an adjacent portion saturated witl` a thermo-plastic resin saturant, the remainder of the sheet saturated with a different thermoplastic resin saturant, the one resin being harder than the other resin and softening to a lesser extent as the temperature to which such saturants may be subjected increases above a temperature of about 65 F. whereby a substantially hard wearing surface is formed.

CLARENCE R. ECKERT. 

